code: def test_str_cat(no_nulls_df):
      """Test outcome for Pandas `.str.cat()` method."""
  
      result = no_nulls_df.process_text(
          column_name="text",
          string_function="cat",
          others=["A", "B", "C", "D"],
      )
  
      expected = no_nulls_df.assign(
          text=no_nulls_df["text"].str.cat(others=["A", "B", "C", "D"])
      )
  
      assert_frame_equal(result, expected)
  
imports: import numpy
  import pandas
  import pytest
  from pandas.testing import assert_frame_equal
label_desc: Use image node_id 13 for calling a global function with example usage: test_str_cat(no_nulls_df) without return types